Halogen bonds with benzene: an assessment of DFT functionals

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Theoretical Chemistry

Background:

• Accurate modeling of non-covalent interactions is crucial in chemistry.
• Density functional theory (DFT) is a widely used method for electronic structure calculations.
• Evaluating the performance of different DFT functionals is essential for reliable predictions.

Purpose of the Study:

• To assess the accuracy of various DFT functionals for modeling interactions between DCl/DBr (D=H, HCC, F, NC) and benzene.
• To compare DFT results with high-level coupled cluster (CCSD(T)) and Møller–Plesset perturbation theory (MP2) calculations.
• To identify the most reliable and cost-effective DFT functionals for these systems.

Main Methods:

• Systematic evaluation of a broad range of DFT functionals.
• Calculations performed against coupled cluster (CCSD(T)) and MP2 reference data.
• Extrapolation to the complete basis set (CBS) limit for high accuracy.

Main Results:

• Double hybrid functionals (B2PLYPD, mPW2PLYPD) showed excellent agreement with CCSD(T)/CBS for energies and geometries.
• Dispersion contributions are critical for accurately describing these interactions.
• ωB97X and M062X offered good performance among less computationally expensive options; ωB97XD and B97D excelled for bromine but not chlorine complexes.

Conclusions:

• Double hybrid DFT functionals, incorporating dispersion, are highly recommended for accurate modeling of halogen-aromatic interactions.
• The choice of functional impacts accuracy, particularly for halogen-specific interactions.
• Dispersion corrections are vital for reliable theoretical predictions in these systems.